Consumable electrodes



March 5, 1963 D. COOPER 3,080,499

CONSUMABLE ELECTRODES Filed May 31. 1960 2 Sizets-Sheet 1 INVENTOR. Donald E. Cooper Agent March 5, 1963 D. E. COOPER CONSUMABLE ELECTRODES Filed May 31. 1960 2 sriee'msneez 2 INVENTOR. Donald E.Cooper Agent United States Patent 3,080,499 CONSUMABLES ELECTRODES Donald E. Qooper, Las Vegas, Nev., assignor to Titanium Metals Corporation of America, New York, N.Y., a corporation of Delaware Filed May 31, 1960, Ser. No. 32,949 4-Clairns. (Cl. 313-357) This invention relates to electrodes employed ina consumable electrode arc melting furnace.

Direct current has heretofore most generally been employed as melting power in consumable electrode arc melting furnaces. A consumable electrode which is circular, or roughly circular, in cross section is progressively melted by heat of an are into a circular cross section cooled crucible. One pole of high amperage source of a direct electric current is connected to the electrode to be melted and the other pole is connected .to the pool of molten metal contalned in the crucible generally by electrical connection to the crucible itself. Multi-phase alternating current would be advantageous to employin such furnaces but use of electrodes of conventional circular shape is not practical since the cross sectional area of a multiplicity of such electrodes leaves a large amount of free space when an assembly of such electrodes is fed down into a circular crucible. To obtain the required volume of metal to form an ingot in the crucible requires corresponding length of a plurality of such electrodes which because of their cross section relationship must be inordinately long.

It is therefore an object of this invention to provide an improved electrode for melting in a consumable electrode arc melting furnace. Another object of this invention is to provide an assembly of a plurality of electrodes adapted for melting in a consumable electrode arc melting furnace. Still another object of this invention is to provide an assembly of a plurality of electrodes adapted for melting in a consumable electrode arc melting furnace in which the cross sectional area of such assembly of electrodes will correspond without excessive free space to the cross section of a circular crucible. These and FIG. 1 illustrates a side view of an electrode embodying features of this invention.

FIG. 2 illustrates a cross section FIG. 1 taken along the line 2-2.

FEG. 3 illustrates an alternative embodiment of an electrode embodying features of this invention.

FIG. 4 illustrates a cross section of the electrode of FIG. 3 taken along the line 4-4.

FIG. 5 illustrates a side view, partially broken out, of an assembly of electrodes of the type illustrated in FIG. 1 as used in a consumable electrode arc melting furnace.

PEG. 6 illustrates a cross section of the electrode assembly of FIG. 5 taken along the line 6-6.

FIG. 7 illustrates a cross section of an assembly of electrodes of the type illustrated in FIGS. 3 and 4 taken along the same general plane as the illustration of FIG. 6.

Referring now particularly to FIGS. 1 and 2 the electrode 10 comprises an elongated metal body of sector shaped cross section as will be seen more clearly from FIG. 2. The electrode has flat sides .12 and an arcuate side 14. Preferably the electrode will have attached to its top and located centrally with respect to the cross sectional area, a stub 16 which is useful for attaching the electrode to support means in an arc melting furnace.

Referring now to FIGS. 3 and 4, an alternative type of electrode 18 is shown which comprises an elongated of the electrode of 3,080,499 Patented Mar. 5, 1963 metal body in which the flat sides illustrated at 12 in FIGS. 1 and 2 .now form one flat side 20 with an arcuate semi-circular cross section. A suitable stub as described previously is shown at 16 attached to the top of this electrode also at the center of its cross sectional area.

An assembly .of electrodes of the type illustrated in FIGS. 1 and 2 is shown in FIGS. 5 and 6. A plurality of three electrodes are employed in each of which the angle between sides '12 is degrees, making the total 360 degrees. The electrodes are arranged in spaced apart, flat side 12 to flat side 12 relationship, as will be apparent from FIG. 6. The spacing between individual electrodes in the assembly should be great enough to prevent arcing directly from electrode to electrode during melting. The three electrodes 10 are maintained in this relationship by removably attaching their studs 16 to support means which in the embodiment illustrated comprise clamps 24 which attach them to the lower ends of three support rods 26. These rods 26 are in turn supported in fixed spaced relationship by attachment of their upper flanges 28 to plate 34 as by bolts 32. Plate 34 is fabricated of insulating material such as Bakelite andis in turn supported by heaw steel plate 34 through which rods 26 pass with insulating space clearance through holes 36. Plate 34 is attached to the end of ram 38 which is in part enclosed in the upper part of furnace housing 40 and by which the assembly is driven upward or downward depending on requirements of the melting arc. Ram 38 will be actuated by suitable and conventional mechanism, .not shown, and its speed and available and well known to those skilled in the art.

The electrode assembly will thus be lowered into a circular cross section crucible 42 which is shown mounted inside the bottom part of a furnace housing as at 44, with the space between being employed as a cooling jacket by circulation of a cooling fluid therethrough. An arc will play between the bottom of electrodes 10 and metal 46 in crucible 42 to produce progressive melting of electrodes 10.

that between the electrode fiat sides and the necessary their arcuate sides and the crucible In FIG. 7 is shown a cross section of the assembly corresponding to FIG. 6 as would be seen when a pair of electrodes according to FIGS. 3 and 4 are employed. These, likewise, are spaced apart in fiat side to fiat side relationship to form an assembly which is advantageous for use with a circular cross section crucible.

Stub 16 is attached to the top of the electrode at the center of its cross sectional area because it vertical uniformity of the In operation, a suitable consumable electrode arc melting furnace is readied for charging, as for instance by separating the lower part of the furnace housing 44 containing the crucible 42, and the electrodes are attached by stubs 16 to support rods 26 by means of clamps 24. A small charge of starting metal may be placed in the bottom of crucible 42 and then the lower part of furnace housing 44 is re-attached to the upper part 40. Electric power of three phase alternating current type, and capable of delivering high amperage, from a source not shown, is connected to each of the electrodes 10 through power leads 48. The electrode assembly is then lowered sively melt t into the crucible-by actuation of ram 38 until an arc is struck between the electrodes and the starting metal. The arc is maintained by suitable and conventional control of actuation of the electrode assembly to progreshe metal of electrodes into a solid ingot in crucible 42, which is cooled during the melting operation according to known principles.

lt'wil-l be apparent that the number of the electrodes in an assembly will depend on the type of current employed. For example, when using single phase current two electrodes of the type illustrated in FIGS. 3 and 4 will be used and the method of operation will lollow that described above for a three phase furnace.

While each of the support rods 26 may be individually vertically driven by conventional means, as will be apparent, the arrangement of the assembly in which the plurality of electrodes are fixed vertically with respect to each other provides somewhat simpler construction. It will be understood by those skilled in the art, that in a plural electrode arc furnace the arc is formed by current transfer from the bottom of one electrode to metal in the crucible and thence to the bottom of another electrode. Arcing to and from each electrode follows successively as the current phases change. It one of the electrodes should for some reason tend to melt ofi to a shorter length than the others, or other, then the arc distance between it and metal in the crucible will become longer, the voltage drop across this distance 'will become higher and less current will pass. As a result the melting rate for the shorter electrode will be reduced automatically until the other electrodes or electrode have been melted off the same length, and uniform arc gap distances will be re-established.

The electrodes, according to this invention, may be fabricated of any metal suitable for melting in a consumable electrode are melting furnace. Such metals include titaniuml, zirconium, steel, stainless steel, nickel, cobalt, molybdenum, tungsten, vanadium and alloys of these, as well as the so called refractory metals and super-alloys.

I claim:

1. A electrode of metal adapted for melting in a consumable electrode arc melting furnace comprising; an elongated metal body of sector shaped cross section having a stub attached to the top ofsaid body in the center of its cross sectional area. 7

2. An assembly of electrodes of metal adapted for melting in a consumable electrode arc melting furnace comprising; a plurality of elongated metal bodies each of sector shaped cross section, the sum of the angles formed by the fiat sides of each of said metal bodies totalling 360 degrees, said metal bodies being attached at their tops to electrode support means and maintained by said electrode support means in spaced-apart, flat side to flat side relationship to each other.

3. An assembly of electrodes of metal adapted for melting in a consumable electrode arc melting furnace employing three-phase electric'cur rent for melting power comprising; a trio of elongated metal bodies each of sector shaped cross section in each of which the fiat sides form an angle of about degrees, said metal bodies being attached at their tops to electrode support means and maintained by said electrode support means in spaced-apart, fiat side to flat side relationship, each to the others.

4. An assembly of electrodes of metal adapted for melting in a consumable electrode arc melting furnace comprising; a plurality of elongated metal bodies each having at least one flat side and a stub attached to the top thereof in the center of its cross sectional area, said metal bodies being maintained by said stubs attached to electrode support means to maintain said metal bodies in spiced-apart, flat side to flat side relationship with each 0t er.

References Cited in the file of this patent FOREIGN PATENTS Nov. 29, 1937 58,696 Norway 

1. A ELECTRODE OF METAL ADAPTED FOR MELTING IN A CONSUMABLE ELECTRODE ARC MELTING FURNACE COMPRISING; AN ELONGATED METAL BODY OF SECTOR SHAPED CROSS SECTION HAVING A STUB ATTACHED TO THE TOP OF SAID BODY IN THE CENTER OF ITS CROSS SECTIONAL AREA. 